Method of making nanomaterial and method of fabricating secondary battery using the same

Abstract

Disclosed are a method of making a nanomaterial and a method of fabricating a lithium secondary battery using the same. The method of making a nanomaterial includes preparing a mixed solution including a metal salt aqueous solution and an alkylamine, and hydrothermally treating the mixed solution.

What is claimed is: 
     
         1 . A method of making a nanomaterial comprising:
 preparing a mixed solution comprising a metal salt aqueous solution and an alkylamine; and   hydrothermally treating the mixed solution.   
     
     
         2 . The method of making a nanomaterial of  claim 1 , wherein the metal salt comprises a chloride, a sulfate, a nitrate, and a combination thereof. 
     
     
         3 . The method of making a nanomaterial of  claim 1 , wherein the metal salt comprises a copper salt, a nickel salt, a lead salt, or a combination thereof. 
     
     
         4 . The method of making a nanomaterial of  claim 3 , wherein the metal salt comprises copper chloride (CuCl 2 ), copper sulfate (CuSO 4 ), or a combination thereof. 
     
     
         5 . The method of making a nanomaterial of  claim 1 , wherein the metal salt and the alkylamine in the mixed solution are present in a mole ratio of about 3:1 to about 15:1. 
     
     
         6 . The method of making a nanomaterial of  claim 1 , wherein the alkylamine comprises a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof:
   CH 3 (CH 2 ) m NH 2   [Chemical Formula 1]
     NH 2 (CH 2 ) n NH 2   [Chemical Formula 2]
   wherein, in the above Chemical Formula 1, m is an integer ranging from 7 to 20, and in the above Chemical Formula 2, n is an integer ranging from 4 to 20.   
     
     
         7 . The method of making a nanomaterial of  claim 6 , wherein the alkylamine comprises decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, or a combination thereof. 
     
     
         8 . The method of making a nanomaterial of  claim 1 , wherein the hydrothermal treatment is performed under an inert gas atmosphere. 
     
     
         9 . The method of making a nanomaterial of  claim 1 , wherein the hydrothermal treatment is performed at 100° C. to 300° C. 
     
     
         10 . The method of making a nanomaterial of  claim 1 , which further comprises washing the hydrothermally-treated nanomaterial. 
     
     
         11 . The method of making a nanomaterial of  claim 10 , wherein the nanomaterial is further heat-treated under an oxygen atmosphere. 
     
     
         12 . A method of preparing a negative active material for a lithium secondary battery, comprising:
 preparing a mixed solution including a metal salt aqueous solution and an alkylamine;   hydrothermally treating the mixed solution to form a nanomaterial; and   heat-treating the nanomaterial.   
     
     
         13 . The method of  claim 12 , wherein the metal salt is a copper salt, a nickel salt, a lead salt, or a combination thereof. 
     
     
         14 . The method of  claim 13 , wherein the metal salt comprises copper chloride (CuCl 2 ), copper sulfate (CuSO 4 ), or a combination thereof. 
     
     
         15 . The method of  claim 12 , wherein the alkylamine comprises a compound represented by the following Chemical Formula 1, a compound represented by the following Chemical Formula 2, or a combination thereof:
   CH 3 (CH 2 ) m NH 2   [Chemical Formula 1]
     NH 2 (CH 2 ) n NH 2   [Chemical Formula 2]
   wherein, in the above Chemical Formula l, m is an integer ranging from 7 to 20, and in the above Chemical Formula 2, n is an integer ranging from 4 to 20.   
     
     
         16 . The method of  claim 12 , wherein the heat treatment is performed under an oxygen atmosphere. 
     
     
         17 . The method of  claim 16 , wherein the heat treatment is performed at a temperature ranging from about 300° C. to about 650° C. for about 2 hours. 
     
     
         18 . The method of  claim 12 , wherein the nanomaterial is oxidized through the heat treatment. 
     
     
         19 . The method of  claim 12 , wherein the nanomaterial has a diameter that is about 1.2 to about 2 times larger after the heat treatment than before the heat treatment. 
     
     
         20 . The method of  claim 19 , wherein the heat-treated nanomaterial has a diameter ranging from about 5 nm to about 50 nm.